Single versus multiple visits for endodontic treatment of permanent teeth: a Cochrane review

BACKGROUNDRoot canal treatment (RoCT), or endodontic treatment, is a common procedure in dentistry. The main indications for RoCT are irreversible pulpitis and necrosis of the dental pulp caused by carious processes, coronal crack or fracture, or dental trauma. Successful RoCT is characterised by an absence of symptoms (i.e. pain) and clinical signs (i.e. swelling and sinus tract) in teeth without radiographic evidence of periodontal involvement (i.e. normal periodontal ligament). The success of RoCT depends on a number of variables related to the pre-operative condition of the tooth, as well as the endodontic procedures. RoCT can be carried out with a single-visit approach, which involves root canal system obturation (filling and sealing) directly aIer instrumentation and irrigation, or with a multiple-visits approach, in which the treatment is completed in two or more sessions and obturation is performed in the last session.This review updates the previous versions published in 2007 and 2016.OBJECTIVESTo evaluate the benefits and harms of completion of root canal treatment (RoCT) in a single visit compared to RoCT over two or more visits, with or without medication, in people aged over 10 years.SEARCH METHODSStandard, extensive Cochrane search methods were used. The latest search date was 25 April 2022.SELECTION CRITERIA AND OUTCOMESRandomised controlled trials and quasi-randomised controlled trials in people needing RoCT comparing completion of RoCT in a single visit compared to RoCT over two or more visits were included.The primary outcomes were tooth extraction and radiological failure after at least one year (i.e. periapical radiolucency). Secondary outcomes were post-operative and post-obturation pain; swelling or flare-up; analgesic use and presence of sinus track or fistula after at least one month. GRADE was used to assess certainty of evidence for each outcome.MAIN RESULTS47 studies were included, with 5805 participants and 5693 teeth analysed. Ten studies were judged at low risk of bias, 17 at high risk of bias and 20 at unclear risk of bias. Only two studies reported data on tooth extraction. No evidence of a difference between treatment in one visit or treatment over multiple visits was found, though with very low certainty (risk ratio, RR = 0.46). No evidence of a difference between single-visit and multiple-visit treatment in terms of radiological failure was found (RR = 0.93; moderate-certainty evidence). Evidence was found of a higher proportion of participants reporting pain within one week in single-visit groups compared to multiple visit groups (RR = 1.55; moderate-certainty evidence). No evidence of a difference was found in the proportion of participants reporting pain until 72 hours post-obturation (RR = 0.97; low-certainty evidence), pain intensity until 72 hours post-obturation (mean difference, MD = 0.26; low-certainty evidence) or pain at one week post-obturation (RR = 1.05; very low-certainty evidence). No evidence of a difference in swelling or flare-up incidence, analgesic use or sinus tract or fistula presence was observed. Subgroup analysis found no differences between single-visit and multiple-visit RoCT for considered outcomes other than proportion of participants reporting post-treatment pain within one week, which was higher in the single-visit groups for vital teeth, and when instrumentation was mechanical.AUTHORS' CONCLUSIONSAs in the previous two versions of the review, there is currently no evidence to suggest that one treatment regimen (single-visit or multiple visit RoCT) is more effective than the other. Neither regimen can prevent pain and other complications in the 12-month post-operative period. There was moderate-certainty evidence of higher proportion of participants reporting pain within one week in single-visit groups compared to multiple-visit groups.In contrast to the results of the last version of the review, there was no difference in analgesic use.